1. Field of the Invention
The invention is directed to a sample cylinder or specimen cylinder with a syringe cone segment, particularly with a filtering device for recovering cell material from body fluids.
2. Description of the Related Art
A filtering device for separating and collecting cells and particles from liquids is known from DE 3719302, which corresponds to U.S. Pat. No. 4,973,450. Efficiency can be increased through the use of this device, particularly in quantitative evaluation methods, e.g., in urine sediment analysis. The device described in the above-cited reference has a specimen cylinder with a syringe cone segment. A filtration tube which is displaceable in the manner of a syringe plunger and has a one-stage or two-stage filter device at one end is inserted into the specimen vessel.
Diagnostic chores, e.g., in the field of urine analysis, require that the particles occurring in urine, such as erythrocytes, leukocytes, urothelial cells, other accompanying cells, crystalline bodies, hyaline cylinders and germs are concentrated and accumulated from a large quantity of liquid, e.g., from a full bladder or from 50-ml or 100-ml samples, without losses in a sediment or in a constant 1-ml amount of liquid. This allows the filtering device to separate and collect cells and particles from liquids, e.g., from urine. Qualitative evaluation is carried out in a manner known per se by adding the specimen by drops to cell counters.
In connection with improved diagnostic possibilities, the known device was improved for cytological purposes where the cell material on microscope slides should have a perfect morphology. To this end, a filtration tube in a known device is guided inside a specimen cylinder with a syringe cone segment and adjoining cylinder segment so as to be sealed against the cylindrical inner wall of the specimen cylinder. When a liquid is drawn in the manner of a syringe and received in the specimen cylinder, and the syringe cone is closed or the specimen cylinder, with the filtration tube removed, is filled with body fluid and then the filtration tube is inserted, the specimen liquid passes through the filtering device when the filtration tube is pressed down against the specimen liquid and collects in the filtration tube or passes out in some other manner.
During the filtration process, additional particles collect on a filter surface which projects particularly over the filtering device. The filtration tube is then usually removed from the specimen cylinder after the specimen liquid has been withdrawn. The particles which have collected on the filter surface can then be transferred to a slide, e.g., for microscopic diagnosis, so that an accumulated suspension in the specimen cylinder which is needed for quantitative analysis is dispensed with.
This print technique has proven extremely successful for obtaining medical preparations. However, in order to transfer the cell material that has collected on the filter surface to slides by this kind of printing, the filtration tube must be removed from the specimen cylinder. For this purpose, after the filtrate or residue has been removed, the device which is now open is turned over and set on a cellulose base, for example. The specimen cylinder can then be pulled out of the filtration tube against considerable resistance through the use of corresponding force. In so doing, remainders of the specimen will inevitably flow down the outer wall and can wet the user's fingers as well as the base. This risk of contamination, for example, in case of infectious material, is disadvantageous and is not tolerable for reasons of hygiene.
Precisely in view of such a risk of contamination, reuse of devices that have already been used should also be ruled out.